1. Field of the Invention
The present invention relates to semiconductor integrated circuit, and more particularly to a diode circuit.
2. Description of the Related Art
A diode has been used as a commutator that commutates a current direction in one way.
FIG. 2 is a diagram showing a voltage between an anode and a cathode of a diode single unit and a current that flows therebetween. The operation of the diode single unit will be described with reference to FIG. 2.
In the case where a voltage between the anode and the cathode is negative, that is, the anode voltage is lower than the cathode voltage, no current flows in the diode ideally.
Also, in the case where the voltage between the anode and the cathode is positive, that is, the anode voltage is higher than the cathode voltage, and the voltage between the anode and the cathode is Vf or higher, a current flows in the diode from the anode toward the cathode.
Ideally, the diode must allow the current to flow therein when the voltage between the anode and the cathode is positive. However, because no current flows unless a voltage of Vf or more is applied, there arises such a problem that an energy of Vfxc3x97current is excessively consumed.
In order to solve the above-mentioned problem, a diode circuit according to the present invention is structured by turning on or off a switch element which is connected in parallel with a diode by the positive/negative of a voltage between an anode and a cathode of the diode.